Automatic carrier box latch of reduced dimensions

ABSTRACT

An automatic latch device for suspended bodies, such as electric light pendants and the like, comprising: a spherical segmentshaped box symmetrical about a plane passing through the center, the two shells comprising said box meeting on said plane and, in addition to being effective as containers, said shells being internally shaped so as to form a seating for members comprising the mechanism and forming part of said members as well. Inside the shell is a cylindrical cup drum, the carrying cable being externally wound thereon, for internally containing a coil spring, a disc having a central pin adhering to said spring, and a clutch plate wherein suitable seatings are formed for the clamping members with said drum. A pin fast with the rear shell has a diametrical slit for coupling the inner end of the spring about which said drum idling rotates, as well as a transverse pin for deviating said carrying cable. Outside the front shell a screw with a resilient washer is arranged and screws down in the pin of the disc adjacent said clutch plate; and a suitably shaped element is also provided for anchoring at the bottom both said carrying cable and the helical driving cable.

United States Patent Caramella [451 Jan. 25, 1972 [54] AUTOMATIC CARRIERBOX LATCH OF REDUCED DIMENSIONS [72] Inventor: Luigi Caramella, Zonalndustriale Roc- [30] Foreign Application Priority Data Dec. 12, 1968Italy ..24968 A/68 521 u.s.c1 ..242/107.3 51] 1m.c1 ..B65h75/48 [58]Field of Search ..242/107,107.1,107.11,107.12,

FOREIGN PATENTS OR APPLICATIONS 168,962 9/1951 Austria ..242/107.3

Austria.... ....242/107.3 Germany ..242/l07 Primary ExaminerStanley N.Gilreath Assistant Examiner-Werner H. Schroeder Attorney-Young &Thompson [57] ABSTRACT An automatic latch device for suspended bodies,such as electric light pendants and the like, comprising: a sphericalsegment-shaped box symmetrical about a plane passing through the center,the two shells comprising said box meeting on said plane and, inaddition to being effective as containers, said shells being internallyshaped so as to form a seating for members comprising the mechanism andforming part of said members as well. Inside the shell is a cylindricalcup drum, the carrying cable being externally wound thereon, forinternally containing a coil spring, a disc having a central pinadhering to said spring, and a clutch plate where-in suitable seatingsare formed for the clamping members with said drum. A pin fast with therear shell has a diametrical slit for coupling the inner end of thespring about which said drum idling rotates, as well as a transverse pinfor deviating said carrying cable. Outside the front shell a screw witha resilient washer is arranged and screws down in the pin of the discadjacent said clutch plate; and a suitably shaped element is alsoprovided for anchoring at the bottom both said carrying cable and thehelical driving cable.

5 Claims, 7 Drawing Figures AUTOMATIC CARRIER BOX LATCH 01F REDUCEDDIMENSIONS This invention relates to an automatic latch device havingboth extremely reduced overall dimensions and highly desirableconstruction details.

The dimensions and compact form thereof allow the use of concealmentdecorative closure plates, the overall size of which is not larger thanthat of common decorative closure plates as used for electric lightpendants not fitted with latch means. Therefore, the use of theautomatic means according to the present invention will not lead to anyadverse result from an aesthetical standpoint.

As to the structural construction, the members comprising the mechanismhave been reduced to the smallest possible size, giving such forms andshapes thereto as to allow for a correct operation of the devicenotwithstanding the reduced dimensions thereof.

The symmetrical shell shape of the box substantially facilitates thelatch-assembling operations and the inner walls thereof form integratingparts of the device in addition to being effective as seatings for theother members.

Another member which has required particular care in designing is theclutch disc or plate which, by using three suitably proportioned rollersassures the mechanism operation notwithstanding the restricteddimensions of the drum wherein said clutch plate is inserted.

The characteristics, as above set forth in short, permit reducing thenumber and dimensions of the mechanism components and making the severalassembling steps extremely simple, and allow a convenient massproduction of the mechanism with resulting low costs.

The present invention also comprises, as an integrating part thereof,the joint terminal for the helical cable to the overhung body, theparticular shape of which facilitates the coupling thereof and preventsthe helical cable from coming out of the sleeve.

More particularly, the device comprises two shells almost equal andsymmetrical to the vertical matching plane and which, besides containingthe other mechanism components, are internally shaped so as to form apart ofthe mechanism.

Internally, a cylindrical cup drum is mounted on the external peripheryof which is wound the carrying cable and the cup is adapted to hold acoil return spring, a disc fast with the central pin and a shapedclamping member with three stop rollers. The braking action is providedby the friction developing on the outer sides of the clamping member asa result of the pressure being exerted on one side by the disc fast withthe pin and on the other side by a suitable washer. This clamping memberis adjustable by tightening or unloosening a screw on the shell outsideand the stem of which is screw threaded within the pin provided withsaid disc.

In the more detailed description of the invention, reference will be hadto the accompanying drawing, wherein the preferred embodiment of thedevice is shown and which, how ever, is to be construed only asexemplary and not in a limiting sense.

In the drawing:

FIG. 1 is a front view ofthe device;

FIG. 2 shows the device in FIG. 1 as rotated through 90;

FIG. 3 shows the shell in FIG. I as seen from the inside with the lowerassociated elements removed;

FIG. 4 shows the rear shell with the inner elements;

FIG. 5 is a sectional exploded view showing all the elements comprisingthe device;

FIG. 6 is a view showing the coupling-shaped member for the helicalcable at its lower end; and

FIG. 7 is a top view ofFIG. 6.

As shown in the drawing, box 8 is in the form of a segment of a spheresymmetrical to the plane passing through the center, the two shells 9and 9 comprising the box meeting on said plane and being kept togetherby an upper screw 10 located sidewise of the slot II for hanging thedevice to the ceiling, the slot being formed with two flanges l2projecting at the top from said two shells 9 and 9', at the bottomhaving a threaded cylindrical extension 113, on which the knurled ring141 is screwed, holding the decorative closure plate (not shown) andbeneath it the cylindrical sleeve 15, the helical driving cable (notshown) leading therefrom. The latter two elements complete the closurefor box 3.

Internally, shell 9 has an annular groove 16 concentric with the centralsquare hole 117 externally associated with the cylindrical seating 18for accommodating the resilient washer l9 and screw 20.

In the threaded extension 13 an axial through hole M is provided asformed by two semicylindrical grooves 21, one in each shell, and twocylindrical seatings 22 displaced to the right of the vertical axis (asseen in FIG. 4) for accommodating, when assembling, the cylindrical pin23 about which the carrier wire 24) departs from the axis of hole 21. Onthe opposite side to seatings 22, the extension halves 13 have twomillings 25 involving the entire extension up to the box curve; bybringing the two millings together, the passage is provided (FIG. 2) forthe driving cable (not shown).

In turn, shell 9 has, in addition to the above-mentioned details, acylindrical seating 26 coaxial with the central pin 27, the pin 27 beingintegral with the shell and having a diametrical slit 27 Reference willnow be made to FIG. 5 for describing the inner members: the cup drum 28has a flanged hole 28' for receiving said pin 27, whereby drum 28 isaccommodated within seating 26. The carrying cable 2% is coiled over theexternal periphery of the drum, while internally the outer end of thecoil spring 29 is attached, the inner end 29' of said spring beingadapted to be inserted into the slit 27' and hence to be secured to pin27. Disc 30 is adjacent said spring and provided with a pin 31 havingacoaxial threaded hole 32. The end portion of said pin is of a squarecross section and fits in the square hole 17 in shell 9. The clutchplate 33 is adjacent said disc 30 and adapted for idling movement on pin31 and has the shape shown in FIG. 4. This clutch plate 33 has threesuitably shaped seatings M accommodating the springs 35 and rollers 36which in their inoperative condition bear tangentially against the innerperiphery of the drum. When the drum rotates anticlockwise, the rollersoffer no resistance due to the convenient slope of the seating, whilewhen tending to rotate clockwise, the rollers will lock the drum andmake it fast with disc 33. Therefore, at the traction step for cable 24the friction provided by tightening said screw 20 must be overcome.Thus, when so operating, the clutch plate 33 rotates between disc 30 andwasher 37, while the resilient washer I9 is also stressed.

The mechanism of box 8 is completed by tube 38 having curved end flangesand which is inserted into the two grooves 21', to facilitate theslidingof cable 24.

The provision is also made for an anchoring member of the helicaldriving cable and carrying cable, as shown in FIGS. 6 and 7. This member39 is screwed in a sleeve 15' equivalent to the upper sleeve 15 and, inturn, having at the bottom a coaxial hole 40 for screwing to theelectric light pendant or the like and for the passage of the drivingcable, said hole mating with the central slot M in the member andconnected with a helical toric groove 42 which is necessarily very deepat the connection area with said slot 41 and reducing to zero as itreaches the top by going about the member.

Member 39 also has an axial hole M, the lower end of the carrying cable24 passing therethrough and being knotted for fastening to the inside ofslot 41.

This particular shape for member 39 aids in connecting the conduct cableend, preventing it from coming out of the sleeve.

What is claimed is:

1. An automatic latch device for suspended electric lights, comprising acircular box divided into two mating shells, a hollow cylindrical drumdisposed in said box, a coil torsion spring disposed in said drum, oneend of said spring being secured to one of said shells, the other end ofsaid spring being secured to said drum, a carrying cable for an electriclight wound about said drum and extending from the lower end of saidbox, a disc having a central pin disposed in said drum next to saidspring, a clutch plate disposed in said drum next to said disc on theside opposite said spring and surrounding said pin, said clutch platehaving members thereon engageable with the interior of said drum topermit rotation of said drum relative to said clutch plate in onedirection and to prevent rotation of said drum relative to said clutchplate in the other direction, a screw extending through the other ofsaid shells and screwthreadedly received within an axial hole in saidpin, and a resilient washer between said screw and said other shellwhereby upon tightening said screw against the action of said resilientwasher, the force is varied which must be exerted in order to unwind thecarrying cable.

2. A device as claimed in claim 1, and a pin secured to said one shelland having a diametrical slit therethrough, said one end of said springbeing disposed in said slit.

3. A device as claimed in claim 1, and a pin parallel to the axis ofsaid drum and carried between said shells adjacent the lower end of saidbox, said carrying cable extending from said drum about a portion of theperiphery of the last-mentioned pin and then downwardly to a saidelectric light.

4. A device as claimed in claim 1, said box having a flat upwardextension having a central hole therethrough for suspending said box anda threaded hole beside said central hole for receiving a screw to securetogether said shells.

5. A device as claimed in claim 1, said box at the bottom having acylindrical extension externally screw threaded and having an axial holetherethrough for said carrying cable, said shells together definingbetween them the last-mentioned axial hole.

1. An automatic latch device for suspended electric lights, comprising acircular box divided into two mating shells, a hollow cylindrical drumdisposed in said box, a coil torsion spring disposed in said drum, oneend of said spring being secured to one of said shells, the other end ofsaid spring being secured to said drum, a carrying cable for an electriclight wound about said drum and extending from the lower end of saidbox, a disc having a central pin disposed in said drum next to saidspring, a clutch plate disposed in said drum next to said disc on theside opposite said spring and surrounding said pin, said clutch platehaving members thereon engageable with the interior of said drum topermit rotation of said drum relative to said clutch plate in onedirection and to prevent rotation of said drum relative to said clutchplate in the other direction, a screw extending through the other ofsaid shells and screwthreadedly received within an axial hole in saidpin, and a resilient washer between said screw and said other shellwhereby upon tightening said screw against the action of said resilientwasher, the force is varied which must be exerted in order to unwind thecarrying cable.
 2. A device as claimed in claim 1, and a pin secured tosaid one shell and having a diametrical slit therethrough, said one endof said spring being disposed in said slit.
 3. A device as claimed inclaim 1, and a pin parallel to the axis of said drum and carried betweensaid shells adjacent the lower end of said box, said carrying cableextending from said drum about a portion of the periphery of thelast-mentioned pin and then downwardly to a said electric light.
 4. Adevice as claimed in claim 1, said box having a flat upward extensionhaving a central hole therethrough for suspending said box and athreaded hole beside said central hole for receiving a screw to securetogether said shells.
 5. A device as claimed in claim 1, said box at thebottom having a cylindrical extension externally screw threaded andhaving an axial hole therethrough for said carrying cable, said shellstogether defining between them the last-mentioned axial hole.